This disclosure is related to the field of geophysical sensing and recording devices deployed in semi-soft ground surfaces, ice and similar environments. More specifically, the disclosure is related to deployment devices for location, signal detection and retrieval of geophysical signals detected by such devices, and retrieval of the devices after signal acquisition and/or recording is completed.
Geophysical sensors known in the art include particle motion responsive sensors such as geophones and accelerometers, and pressure or pressure time gradient sensor such as hydrophones, for detecting seismic energy originating in the Earth's subsurface or reflected from subsurface acoustic impedance boundaries after having seismic energy imparted thereto by a controlled acoustic energy source. Some embodiments of such geophysical sensors may have associated therewith self-contained data recording devices that can operate autonomously. Such devices may be referred to as recording nodes.
Some geophysical sensors and/or recording nodes may be deployed proximate the ground surface for land based geophysical surveys. Some geophysical sensors and/or recording nodes may be deployed into semi-soft surface materials, such as mud proximate the bottom of a shallow body of water, sand in desert and similar geographic areas and in holes bored through ice in geographic areas having ice cover during at least some times of the year. In the foregoing types of geographic areas, it may become difficult to locate and/or retrieve the geophysical sensor and/or recording node after deployment for a length of time; ice can freeze proximate the sensor or node in place, and sand, snow, and/or mud can cover the sensor or node.